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Bandak’s hydraulic bolt tensioning solution increases efficiency in offshore wind

Bandak offers hydraulic bolt tensioning systems to the offshore wind industry, saving time and money by simplifying installation and reducing maintenance downtime. “We help to facilitate the transition to renewables using our 40 years of experience in oil and gas,” says Håvard Øygarden, Engineering Manager at Bandak.Published 29 June 2022 (updated 7 Feb 2024) · 3 min read
Multiple bolt tensioner Bandak’s hydraulic bolt tensioning solution

At a glance

  • Hydraulic bolt tensioner for offshore wind
  • Lightweight, multiple bolt design
  • Higher efficiency, lower cost

One offshore wind turbine contains about 25 000 bolts. All of these bolts must be tightened precisely as the turbines needs to withstand huge loads and the forces of nature. They also need to be maintained over time to prevent breakdowns.

“Offshore wind farms present challenges not found on land. Both assembly and maintenance can be more difficult and dangerous, not to mention significantly more costly due to the cost of vessel charter. A relatively small component such as a bolt is crucial to the integrity of the structure,” says Øygarden.

Higher efficiency with bolt tensioning

Bandak has designed a hydraulic bolt tensioner suitable for the offshore wind industry. The solution can be used for both bottom-fixed and floating wind farms and is designed for M14 to M140 bolts.

Bolt tensioning reduces maintenance and downtime compared to conventional torquing. “Tensioning is more accurate, while torquing involves some guesswork. Our solution gives a safer, tighter and more reliable fit. This keeps the wind farms operating at optimal capacity,” says Øygarden.

Aside from offering a standard bolt tensioning solution, Bandak has experience and extensive expertise in designing tools for areas where there are space challenges in terms of height or width.

Bandak’s solution is also lightweight to meet the needs of offshore wind farms.

“We have taken an existing version of our conventional bolt tensioner and redesigned it to be as light as possible. Offshore wind emphasises lightweight tools, in part because wind farm assembly is done on site in harsh conditions,” Øygarden explains.

In addition, he points out, “Because the design is ready and proven, we can come up with a customised solution in a short time.”

Standard single bolt tensioner
Standard single bolt tensioner

Multiple bolt tensioner

Bandak’s multiple bolt tensioner is made to pretension several bolts simultaneously, improving efficiency in offshore wind construction. “We have a multiple bolt tensioner on the market that pretensions 16 bolts at the same time,” says Øygarden.

Bandak has proven results from years of delivering multiple bolt tensioning solutions to the oil and gas industry. “Our tools have reduced installation time from 70 to 19 hours on two offshore platforms on the Norwegian continental shelf,” he says.

Custom-made bolt tensioner M52 OD 100mm
Custom-made bolt tensioner M52 OD 100mm

Important part of a huge industry

As offshore wind expands to a USD 1 trillion industry, the need for advanced bolt tensioning tools will increase as well.

“We are an expert in hydraulic bolt tensioning solutions for other industries and have been delivering them since 1966. Now we are offering our technology and expertise to the offshore wind industry. We hope this can be our foot in the door of renewable energy,” says Øygarden.

Founded in 1938, Bandak provides industrial products for the energy, maritime and general industry sectors. The company is a well-known mechanical supplier in the fields of advanced machining, structural welding, grinding, thermal coating, and assembly and testing.

“We pride ourselves on being a reliable solutions provider from subsea to space,” Øygarden concludes.

Bandak AS

Bandak AS

Hantovegen 328, 3825 LUNDE, Norway


Håvard Øygarden

Engineering Manager

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